Newer versions of GDB need pthread debugging support if threads are
enabled, which is always the case for glibc but is a configure option
for uClibc.
We have solved this for internal toolchains by selecting the
BR2_PTHREAD_DEBUG option from the GDB selection if needed, but as this
option isn't available when ctng/external toolchains are used, mconf
prints ugly warnings and the build may fail if an external uClibc
toolchain without pthread debugging support is used.
Fix it by introducing 2 more hidden config options:
- BR2_TOOLCHAIN_HAS_THREADS_DEBUG
- BR2_TOOLCHAIN_HAS_THREADS_DEBUG_IF_NEEDED
The first tells us if the toolchain HAS pthreads debugging support,
and is checked by check_uclibc_feature in helper.mk for external uClibc
based toolchains.
The second tells us if the toolchain is ABLE TO provide pthreads debugging
support if threads are enabled, either because it's an internal toolchain
where we can force enable it or an external glibc/eglibc toolchain or
uClibc with the option enabled.
Crosstool-ng forcibly enables this support, so those will always work.
The preconfigured uClibc-based toolchains we have also all enable it.
Finally, show a comment if this isn't the case so the (external toolchain)
user knows why. This is placed outside the choice option, as menuconfig
has a bug where it doesn't show choice selections which only contain
comments.
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>